Rockwell Automation 8520 9/Series Hardware TAB 5 - Manual (Page 143)

Section 5B
9/440HR CNC/Drive System
5B-69
System Grounding
Figure 5B.53 illustrates the recommended 9/440HR grounding scheme.
All grounds terminate on a single point. Note there are two separate
ground wires going to the system module. One ground connects to PE of
the system module power terminal block, the other connects to the ground
stud found just beneath the wiring board on the mounting bracket for the
9/440HR CNC assembly.
Figure 5B.50
Recommended High–resolution Grounding Scheme (Series A/B)
9/440 High–resolution
System Module
Open
cover
9/440 High–resolution
CNC Assembly
PE Stud
Power Terminal Block
PE Power Terminal Block Ground